[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 240004
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST TUE DEC 23 2014

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF
SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE
EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE
IMAGERY...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL
ANALYSIS.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2345 UTC.

...SPECIAL FEATURES...

...GALE-FORCE WINDS FORECAST FOR THE GULF OF MEXICO...

A COLD FRONT CURRENTLY MOVING ACROSS THE NW GULF IS FORECAST TO
EXTEND FROM SOUTHERN MISSISSIPPI SW TO THE BAY OF CAMPECHE WED
MORNING. A TIGHT PRESSURE GRADIENT BETWEEN THE FRONT AND A RIDGE
BEHIND IT WILL SUPPORT GALE-FORCE N WINDS AND SEA HEIGHTS TO 8
FT W OF FRONT. GALE WINDS ON THE GULF ARE FORECAST THROUGH WED
NIGHT. PLEASE READ THE HIGH SEAS FORECAST...MIAHSFAT2/FZNT02
KNHC...AND THE OFFSHORE FORECAST...MIAOFFNT4/FZNT24 KNHC...FOR
MORE DETAILS.

...THE ITCZ/THE MONSOON TROUGH...

THE MONSOON TROUGH CROSSES THE COAST OF AFRICA NEAR 05N09W AND
CONTINUES OVER THE E ATLC WATERS NEAR 05N15W. THE ITCZ BEGINS
NEAR 05N15W AND CONTINUES ALONG 04N30W TO 03N48W. SCATTERED
MODERATE CONVECTION AND ISOLATED TSTMS ARE FROM 04N-06N BETWEEN
18W-22W.

...DISCUSSION...

GULF OF MEXICO...

SOUTHWESTERLY FLOW ALOFT BETWEEN A MIDDLE-LEVEL TROUGH ALONG THE
CENTRAL U.S. WITH BASE OVER CENTRAL MEXICO AND A BROAD
ANTICYCLONE ANCHORED N OF HISPANIOLA CONTINUES TO ADVECT
MOISTURE FROM THE EPAC ITCZ GREAT PORTIONS OF THE GULF. THE
TROUGH ALOFT...SUPPORTS A COLD FRONT THAT EXTENDS FROM A 1000 MB
LOW OVER SE LOUISIANA SW TO 27N95W TO 25N97W. AHEAD OF THE
FRONT...S-SE WIND FLOW RANGING FROM 15-25 KT CONTINUES TO ADVECT
LOW-LEVEL MOISTURE FROM THE CARIBBEAN INTO GULF...WHICH ALONG A
DIFFLUENT ENVIRONMENT ALOFT SUPPORT HEAVY SHOWERS AND TSTMS N OF
27N BETWEEN 89W-92W AND N OF 28N E OF 87W. LOW PRESSURE WILL
CONTINUE ACROSS THE GULF THROUGH TONIGHT...THEN SHIFTS TO THE
EASTERN BASIN WED MORNING ALONG WITH THE COLD FRONT. GALE-FORCE
WINDS ARE FORECAST TO BEGIN W OF THE FRONT LATER TONIGHT
CONTINUING THROUGH WED NIGHT. SEE SPECIAL FEATURES ABOVE. THE
COLD FRONT IS FORECAST TO EXIT THE BASIN THU MORNING.

CARIBBEAN SEA...

A VERY STABLE ENVIRONMENT CONSISTING OF A BROAD MIDDLE-LEVEL
ANTICYCLONE ANCHORED N OF HISPANIOLA...A RIDGE AT THE UPPER-
LEVELS AND DRY AIR SUBSIDENCE CONTINUES TO SUPPORT FAIR WEATHER
ACROSS THE BASIN. PATCHES OF SHALLOW MOISTURE EMBEDDED IN THE
TRADE WIND FLOW SUPPORT SCATTERED CLOUDINESS AND POSSIBLE
ISOLATED SHOWERS ACROSS PUERTO RICO COASTAL WATERS AND DOMINICAN
REPUBLIC. TRADES RANGING FROM 20-25 KT HAVE EXTENDED ACROSS THE
ENTIRE BASIN EXCEPT FOR SOUTHERN COASTAL WATERS OF THE GREATER
ANTILLES AND S OF 12N WHERE WINDS ARE UP TO 15 KT. FOR THE
EASTERN AND WESTERN BASIN...TRADES ON THIS RANGE ARE FORECAST TO
REMAIN THROUGH WED MORNING. HOWEVER...FOR THE CENTRAL CARIBBEAN
WINDS OF 20-25 KT ARE FORECAST TO PREVAIL TROUGH FRIDAY NIGHT. A
COLD FRONT WILL EXIT THE GULF OF MEXICO THU MORNING WITH TAIL
EXTENDING FROM WESTERN CUBA SW TO BELIZE COASTAL WATERS.

HISPANIOLA...

A VERY STABLE ENVIRONMENT ALOFT CONTINUES TO SUPPORT FAIR
WEATHER ACROSS THE ISLAND. THESE WEATHER CONDITIONS ARE EXPECTED
TO PREVAIL THROUGH THU NIGHT AS DEEP LAYER DRY AIR WILL
PREDOMINATE.

ATLANTIC OCEAN...

SURFACE HIGH PRESSURE ANCHORED BY A PAIR OF HIGHS ON THE NW ATLC
EXTENDS A RIDGE AXIS SW TO THE SW N ATLC WATERS. A WEAKNESS IN
THE RIDGE IS BEING ANALYZED AS A SURFACE TROUGH ALONG 24N72W TO
18N71W WITH NO CONVECTION ASSOCIATED WITH IT. FARTHER
EAST...ANOTHER SURFACE TROUGH EXTENDS FROM 22N50W TO 17N51W
LACKING CONVECTION. OVER THE CENTRAL BASIN...A NARROW AND
ELONGATED TROUGH ALOFT WITH BASE NEAR 25N34W SUPPORTS A COLD
FRONT N OF THE AREA OF DISCUSSION WITH TAIL EXTENDING FROM
30N34W TO 26N34W. SCATTERED MODERATE CONVECTION AND ISOLATED
TSTMS ARE N OF 25N BETWEEN 30W-42W. SURFACE RIDGING DOMINATES E
OF THE FRONT. A NEW COLD FRONT WILL ENTER THE SW BASIN BY THU
MORNING.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$
RAMOS

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